Press



A. A. BYERLEIN July 2, 1946.

PRESS Filed March 27, '1945 y /3/ f/.ga

5 Sheets-Sheet 1 July 2, 1946.. A. A. BYERLEIN 2,403,339

PRESS Filed March 27, 1943' 5 Sheets-SheefI 2 2 .n 49) 2// #1L-a I, i l ,H #4

July 2, 1946.

A. A. BYERLE!N PRESS Filed March 27, 1943 5 Sheets-Shee'c 3 grr/umm" ma y 77 wir Jul'y 2, 1946. A. A. BYERLEIN PRESS Filed aaron 27, 1945.

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. b M n..-nWHWwww???am. 3 g l o O. 3 M Q 4 Patented July 2, 1946 v PRESS Y Arthur A. Byerlein, Detroit, Mich., assigner to General Machinery; Corporation,

Hamilton,

Ghio, a corporation of Delaware ApplicationMal-ch 27, 1943, Serial No. 480,765

. 25 Claims.

. l This invention relates to stamping and drawing presses, such as are used for forming metal sheets as in the manufacture of automobile bodies .and parts thereof, and the like; Vand more par- I'ticularly -to air cushion mechanisms used in such presses and controls therefor.

vPresses for stamping for 'forming operations have been widely used, and in many instancesfare quite enormous-and complicated machines used for stamping orforming large and intricate prod- 1" ucts, involving also the use -of very intricate and complicated dies and 'sometimes with Widely varying 'draws or reverse draws in the forming of the same intricately shaped piece. And such presses and manufacturing operations to be per^- formed by them have-often presented problems long unrecognized as such or long defying -eiforts lto solve them or of such difficultcharacter as to require greatest ingenuity to create practical and commercial handling. An apt illustration is the use of mechanicallyoperating drawing presses for use in the making ofv productsvsuch as automobilebodies, inwhich thin sheets of metal of considerable size are formed, the operation requiring 'that this thin sheet beso held by the' operating parts of the -press that'it will draw or flow in the dies over the edges of the dies and between the holding members, so as to give substantially uniform flowing of the sheet into the intricate forms required, and thus to {produce a` 30 nished product in which the thickness of the sheet is substantially unchanged and which is free from objectionable wrinkling or tearing. In-

asmuch as the greater part of automobile bodies have heretofore been formed from sheets of steel' eral drawing operations of Varying depths and also reverse drawing operations, it is readily seen, as universally recognized in the industry, that such operations require that the enormous presses and dies and the controls therefor should act with precision, to exert the right amount of such problems of providing and operating the Ipresses, even of the largest size, with the accuracy usually expected only in precision instruments.

And, in such operations the mechanisms must be such that the metal sheet may be caused to flow and to be formed from flat sheets into shapes requiring drawing operations of a depth of ten or twelve inches or more, which depth draws may be immediately adjacent a very shallow draw or forming operation in the same sheet, and each ci' which may have toI be formed in conjunction with a reverse draw within corresponding ranges.

While such operations have required large presses with intricate operating mechanisms, capable of exerting enormous pressures it has also been requisite that they be capable of operating `'within the very narrow limits required to cause owing of the thin sheet of metal into the intri- Vcate form desired without objectionably varying the thickness of the sheet and without leaving wrinkles or rough spots which would immediately show up as defacing highlights when the surface of the formed metal part is painted and on the other hand without exerting such pressures as would unduly resist the flowing of the metal and thus cause the sheet to tear. In some of these presses it has been a practice for years to provide for use, and as a ilexible controlling element thereof, air cushions, arranged ordinarily in the bed of the press and operative through the bolster plate by means of pins of proper length, so that certain portions of the operation might be performed against the controlled yielding resistance of theY air cushion,-such air cushion mechanisms permitting of more readily controlling the holding pressures within the desired narrow limits upon the outer edges of the metal sheet and also permitting of more ready control of pressures in localized .portions of the dies, of more ready control during certain reverse drawing operations occurring during one complete cycle of the press, and also serving as a lift out mechanism to lift o1' eject the formed piece from the dies or permit its more ready removal by the workman.

The present invention relates [particularly to presses presenting such problems and operating intricacies and diculties as referred to, and one `ofthe principal objects of the invention is to propressure at the right place at the right time, in vide such a press with air cushion mechanisms order that these results on such a thin sheet of metal may be attained. vAnd the more recent great increase in the use of forming presses working on the lighter metals and on readily flowable and controls therefor, so constructed and arranged as to meet widely varying operations, that greater effectiveness and accuracy may be attained in opera-tion and with efciencies and plastics as in the aviation industry presents also 56 economy in operation,

Another object of the invention is to provide air cushion mechanism having means for readily controlling the effective stroke of the pin supporting member during operation so that the air cushion may be readily and easily adjusted to varying dies and draws and operating conditions While maintaining maximum effectiveness in operation.

Still another object of the invention is to provide such air cushion mechanism in which the effective travel of the portion exerting pressure upon a part o-f the die or sheet being formed may be readily restricted, by easily elected adjustment, to correspond substantially with that stroke required thus utilizingr the minimum amount of pressure air for the adjustment 'se-l Y lected as required for the particular operation,

.to be performed must be selected or prepared,

which results in substantial economies in operation due to economizing on the labor time inrvolved in shifting from one die operation to another; it being understood that such presses are often used in production lines including a conside'rable.'numberof presses each of which performs its own .particular operation (such as blanking out the .shape of the metal sheet, die

cutting proper holes and openings, performing the intricate shaping, hanging, trimming, etc.) so that any delaying or spoilage in the operations "f one press affects the time and economies of operation of the whole line,

Still another object of the invention is to provide such air cushion mechanism and controls for usein such press in which objectionable pressures are prevented from being exerted by the air cushion mechanism against the completely formed metal, with resultant deformation or damage,.in a very simple manner and without the use of the intricate and involved locking or hold-down mechanisms heretofore employed.

Still another object is to provide for accomplishing this desired result by means of controls which cause wastage of only very small fractions of the necessary operating pressure air, thus securing this highly desirable result with comparatively very simple and effective mechanism and controls and without adverse comparative economies in operation.

Still a furtherobject of the invention is to provide an air cushion mechanism of the char- 'acter described which may be manufactured of standard dimensions but to operate satisfactorily in presses having varying bed and die dimensions, thus permitting of greatly reduced cost of manufacture as compared with air cushion mechanisms as heretofore supplied which have been generally designed and constructed of dimensions and proportions to nt the particular press bed in which they are to be used, and yet such as to provide the operating advantages of this in- Vention.

Also another object of the invention is to provide such air cushion and control mechanism which readily permits of its use for stamping operations and asa lift-out, and also in drawing operations, and whichis constructed: and operable to secure operating economies by controlling the amount of pressure air required according to the type of operation to be performed.

Other objects and advantages of the invention Will be apparent from the descrip-tion and drawings and in the appended claims. Y

In the drawings, in which like characters of reference designate like parts'throughout the several views thereof, is illustrated a preferred embodiment of the invention:

Fig. 1 is a side elevational view of a press including the air cushion mechanisms and controls, with parts thereof shown in dotted lines;

Fig. 2 is an enlarged view of the air cushion mechanisms and parts of the controls (two of the air cushions and associated parts being shown) and with partsshown in vertical section, along the vertical central plane of the air cushion mechanism and with a bolster plate and simplied diagrammatic form of die also shown in cross section in conjunction therewith, thes'sectional view being approximately along the line 2-2 of Fig. 3;

Fig. 3 is a vertical cross sectional view along the line 3-3 of Fig. 2 with the air cushion shown in elevation and with the bolster plate and diagrammatic die parts and the upper press slide omitted; l

Fig. 4 is a horizontal sectional view through the press along the line 4-4 of Fig. 2; and with the lower part of one of the air cushion mechanisms in section, as indicated also by the line 4-4 of Fig. 2 toshow certain details of construction;

Fig 5 is an enlarged horizontal sectional view through the lower part of one of the air cushion mechanisms, corresponding to the smaller view at the right of Fig. 4, and along the line 4 4 of Fig. 2, to show details of construction more clearly;

Fig. 6 is a sectional View through the lower part of one of the air cushion mechanisms along the line 6-6 of Fig. 2, showing certain details of construction;

Fig. 'I is an elevational detail view of one of the air cushion mechanisms corresponding to Fig. 2 and with parts broken away to more clearly show the passages for the pressure air;

Fig. 8 is a vertical sectional view through one of the air control valves for the air cushion, said view being along a vertical plane at right angles to the plane of Fig. 2;

Fig. 9 is a corresponding sectional view through the same valve with the movable valve member in a diierent operating position;

Fig. l0 is a diagrammatic and schematic view showing the positioning of the parts and the operation during a cycle of the press, when performing a drawing operation;

Fig. 11 is a diagrammatic and schematic view showing the positioning of the parts and the operation during a cycle of the press, when performing a stamping operation and arranged for the air cushion to act as a lift-out after the stamping is formed and at the proper place in the cycle of operation of the press;

Fig. 12 is a detail view in elevation of one of the gages for indicating certain settings in adjusting the air cushion mechanisms for varying depthsdof draw;

Fig. 1`3 is a detail View in elevation of another of the gages for indicating certain other settings in adjusting the air cushion mechanisms for corresponding variations in depth of draw;

Fig. 14 is a diagrammatic view showing Wiring diagram and controls for the air cushion mechanisms and the solenoid operated valves, and also the rotary limit switch operated by the press for automatically actuating the controls, and the push button station for manual control;

Fig. l5 is a somewhat diagrammatic view, with parts shown in vertical section, of one of the solenoid operated valves;

Fig 16 is a somewhat diagrammatic view with parts shown in vertical section of the other solenoi-d operated valve;

Fig. l'l is a detail View showing diagrammatically the construction and operation of one of the switches shown in Fig, 14, for operation of the solenoid valves, and of one of the cams of the cam actuating mechanism; and

Fig. i8 is a somewhat diagrammatic View of the solenoid operated brake mechanism.

In the preferred embodiment illustrated in the drawings, the press is shown as comprising a bed member 25 which is suitably supported upon the concrete iioor or upon other suitable foundation; this bed having aixed thereto upwardly extending upright members 2 I, and a movable die slide member which is constructed properly to reciprocate up and down during operation, within the upright members 2|, such upper slide member being designated generally by the numeral 22 and having suitable bolt receiving or other means whereby the upper die may be secured to the lower face thereof.

The bed member 20 is shown as a hollow casting which is adapted to receive a bolster plate, 35, this plate extending over the opening in the bed and being provided with suitable means, such as the usual bolt receivers whereby the lower die member may be fastened thereto for operation. As shown a cross web 22' is provided, extending across the space within the bed and interconnecting the opposite walls and also dividing such space into two compartments. The die is shown for illustrative purposes in very simple, diagrammatic form, and as of limited extent covering only part of the bolster plate or bed, in

Fig. 2, the lower, male member, being designated v by the numeral 23 and the upper female member by the numeral 24. The die shown is one for performing a simple stamping or drawing operation and is provided with a ring or plate member which, in operation, can serve dual purposesone, as a blank holder for holding the outer edges of the sheet of metal to be formed, which is designated by the numeral 25, so that the sheet of metal is held with the proper pressure between the upper face of the blank holder 25 and the bottom face of the upper die 24 with the holding pressures controlled by the air cushion so that as the upper die descends the metal will be drawn between these cooperating faces under such controlled pressure that it will not be so loosely held ber 25, under the action of the air cushion mech- 7 anism likewise serves as a lift-out to lift the formed metal off of the lower die after the forming operation has been completed and at a properly selected time during the period in which the upper slide completes the latter or upward travel of a cycle of the press. The bolster plate 30 is held to the bed 20 in suitable manner, as by means of bolts or wedges or clamping members held by bolts, which are suitably threaded into the bed but not shown as they may be of desired conventional form. If the press is desired to be used to effect drawing operations, pressure cushions. such as the air cushions, indicated generally by the numeral 34, which are mounted and suitably supported within the bed and below the bolster plate will be properly utilized, as hereinafter described. If a simple stamping operation is to be performed these cushions need not be utilized except to operate the blank holder 25 as a liftout member.

In the embodiment shown each of the air cushions is cylindrical in cross section, as illustrated diagrammatically by dotted lines in Fig. 4. The bolster plate 30 has the usual large number of holes, designated by the numeral 35 (see Fig. 2) with several of these holes shown as intersected by the plane of the section at the left of Fig. 2 and therefore in full lines and others shown in dotted lines as illustrated. These holes are for accommodating pins, the upper ends of which, shown, support the holding or lift-out ring 25-il; being understood that the number of holes and the number of pins used will be varied under varying operating conditions, to support the ring 25 and also to support any movable portion of the die which is constructed to act against the metal sheet at the desired part thereof and over the desired range in the cycle of operation of the press so as to give proper and accurate control of the forming operation. As shown these pins are designated. by the numeral 3S, and each of them at its lower end rests upon and is supported by a movable plate 40, which in turn rests upon and is bolted by bolts 31 to the upper face of the movable portion of the air cushion, which. is designated generally by the numeral 4|, and which for purposes of simplicity herein will be called the piston (inasmuch as it is the portion of the air cushion which is movable under the action of the pressure air and in theoperation of the press). By the construction thus described the pressure acting upon the piston 4l will be transmitted through the plate 40 to the pins 36 and thus suitable pressure can be transmitted through these pins to the draw ring or blank holder 25, or a pressure controlled portion of the die members.

As shown particularly in Fig` 2 the upper or head portion of the piston which is indicated also by the numeral 4l has a central depending cylindrical portion 42 and an outer cylindrical depending portion or skirt 43, the portions 42 and 43 being spaced from each other radially a suincient distance to receive the other main member of the air cushion mechanism which is designated generally by the numeral 45 and which is supported from the bed, and preferably ainxed to the bed so that it is held firmly in place during operations. As shown in Fig. 3 this stationary portion 45 carries outstanding flanges or lugs 46, which seat upon inwardly extending supporting anges 41 shown as formed integrally with the bed and etxending inwardly from the inside wall thereof to provide a support for the flanges 46, the two being bolted together by means of the bolts 48 which permit of ready insertion or removal of the air cushions when the bolster plate is removed for access to the space inside the bed.

Each air cushion, whether cylindrical or of other cross sectional shape, may be made of standard size, and of over-all outside dimensions such as to permit of ready positioning of the air cushion in the space inside the bed of the press, the construction being such that neither of the parts 43, 45 need accurately t within the bed or against guiding means therein (the movable member 43 being properly guided as hereinafter described) thus permitting use of standard size air cushion mechanism with substantial variations in bed dimensions, which variations are the rule in the manufacture of large presses, most of which are designed to somewhat special dimensions as to width and depth of the bed to meet conditions existing in a specic plant or to accommodate certain predetermined sizes of dies required for the operation which the press is to perform. The upper surface of the portion 4| is formed or machined to receive the lower properly finished face of the plate 40 so that the plate 40 in turn will properly support the pins 36, and this plate 40 may be made of proper size to be inserted in the bed, with about 1/2" clearance on all four sides. Projections 49 formed on the end Walls of the bed and on the opposite sides of the cross web 23 prevent excessive rotation of piston 4|, and therefore a standard size air cushion mechanism may be provided for beds of substantially varying dimensions and the necessary dimensions of the bed met by making the plate 40 of the proper size to accommodate itself for operation in the cushion compartments of the bed. This is of greatcommercial importance because it permits of the manufacturing of a few sizes of standard dimension air cushion mechanisms as standard and in quantity production (as opposed to individual manufacture of mechanisms each of which is of special size, dimensions, etc., to fit a special size press) and which can be readily supported in -beds of substantially varying dimensions-across or fore and aft-with the variations in size easily taken care of by increasing or decreasing the inward extent of the portions 41 so that they will properly receive and support the air cushion mechanism, which can be readily accomplished by simple operations in the casting or fabricating of the press bed. And by varying the dimensions of the plate 40 so that it will have suflicient extent to support all of the necessary pins 36, the standard cushion can be used in varying size presses and beds and with as good results as those specially designed. This permits of greatly reduced manufacturing costs and of considerable economy in capital investment by the press user, which is reflected in operating economies. Also it permits the press manufacturer to stock the air cushions so that in the event of required replacement of a cushion. because of break down or accident, a substitute may be made available promptly to thus minimize interruption of operation of the particular press, or the line of which it is a part.

The lower fixed member 45 has its inner Wall portion 5:3 properly machined to receive bushings 52 which provide suitable sliding and guiding contact for the downward extension 42, and as the lower end 5| of this member 42 serves as a piston head against which the pressure air is exerted, suitable piston packing 53 is provided in the lower end of the wall 5B, so that the parts may operate under air pressure satisfactorily and without undue air leakage. Also, the guide walls Ell and the guide extension 42 are of such substantial diameter and length that the spacing of bushings 52 provides for such guiding of the portion 42 that external guides are unnecessary and the movable piston member reciprocates in operation adequately guided by this construction. A

suitable packing or piston ring 56 is likewise provided between the outer piston skirt wall 43 and upper end of stationary member 45.

As will be clear from the above there are two air pressure spaces-one, the space 6D which is provided in the lower part oi the stationary member 45 and below the piston head 5| of the central depending portion 42 and the other the space which is provided above the upper end of the stationary member 45 and below the upper head portion 4! of the movable piston.

Pressure air is supplied from a usual surge tank G5, illustrated diagrammatically in Figs. l0 and ll and also illustrated diagrammatically in Fig. l. This surge tank being an air pressure storage tank of considerable capacity which may be conveniently connected to the pressure air-system of the plant, and which wil] usually maintain within said tank a pressure of about to 100 lbs. per square inch, the surge tank being supplied by a, regulating valve, 68, illustrated diagrammatically and which' can be of any suitable operating construction, so that the pressure in the tank can be adjusted to and maintained at any pressure up to the maximum available from the factory air pressure line. When the pressure in the storage or surge tank is set for any given die and forming operation it will remain approximately constant and can be changed from time to time as different dies and different drawing operations may require.

The variations in pressure exerted by the air cushion upon the pins 36 during a cycle of operation of th'e press should be so limited in variation that objectionable and adverse eiiects upon the metal being formed will not occur. In practice it has been found that very satisfactory results are secured if the increase in pressure which results as the piston is pressed down and the pressure air is forced to surge back from the air pressure spaces into the surge tank is limited so that it will not increase more than about 15%; although' this increase in pressure may be readily controlled, as by varying the relative capacities of the pressure spaces in the air cushion and the storage space in the surge tank.

The pipe and pressure regulating valve for controlling the introduction of air into the surge tank are not shown in detail as these are well understood and explanation with respect thereto is unnecessary. The interior of the surge tank has a pipe 61 connected thereinto, illustrated diagrammatically in Figs. l0 and llJ through which the interior of the surge tank may be connected to or disconnected from either or both of the pressure spaces B, 5|.

This pipe 67 is connected to a two-way solenoid operated valve 68 illustrated diagrammatically in Figs. 10 and l1, and shown in somewhat diagrammatic detail in Fig. 16, as it may be of any suitable construction available commercially. This valve 68 has an outlet pipe 69 leading off from it, which in turn is connected to a suitable three-way solenoid operated valve lil, also illustrated diagrammatically in Figs. 10 and 1l and in Figs. 3 and 4, and shown in somewhat diagrammatic detail in Fig. 15 and which also may be of any suitable construction available commercially. This three-way solenoid valve has leading 01T therefrom a pipe 15, which as sh'own diagrammatically in Figs. 10 and 11 and which, as shown also in Figs. 2, 3 and 4 extends upwardly and connects onto the pipe extension 18 which has an elbow or Y connection therein to provide two branches one of which, 11, is connected through the Wall of the stationary member 45 into the pressure space Si! and the other branch of which, 80, is connected through the Wall f the member 45 to a passage 8| which extends upwardly and the upper end of which opens into the pressure space This branch S0 has a three-way valve designated generally by the numeral 85, and the detailed construction of which is shown in Figs. 8 and 9, which valve is illustrated as of the turn plug character, the rotatable plug 86 having a central opening with three passageways so arranged that in one position, as shown in Fig. 8, the branch 80 is open to permit pressure air to ow therethrough to and from th'e upper pressure space 6| and in another position, illustrated in Fig. 9, is so arranged as to connect the upper cylinder space to the atmosphere through the discharge or exhaust branch 81, while disconnecting this cylinder space 6| from the source of pressure air. This valve is provided with an extending shaft or key 88 so that it may be turned to connect both pressure spaces 60 and 6| to the surge tank, or only the lower space Ell-the ccnnection of course being through the pipe 19, the branches and 80, and the solenoid operated valves--the setting being thus independently eiected.

The spaces 90, shown in Figs. 2 and 7 (and also diagrammatically in Figs. 10 and 11), are primarily for the purpose of lightening construction, while giving sucient radial spacing to the Walls of the stationary part 45 to give the desired pressure areas effective in the spaces 60 and 6|.

The end portion 5| and the lower end of the member 45 are provided with axially arranged passages95 and 95 which receive an adjustable rod Aor bolt 96, the upper end of which passes through said passages and is provided above the lower piston end 5| with a stop member 91, sho'wn as a nut which is threaded on the upper end of 96 and keyed thereto to provide'a Xe'd collar or stop,A the lower face of'which is effective to abut against the upper' face of the piston 5| so as to limit the upward rise of the piston 4| under the action of the air pressure. The lower end of this adjustable rod 96 is threadedly engaged inside of an adjusting nut |00, the outer face of which is rotatably mounted within a cylindrical sleeve or bearing member IDI, which member |0| is keyed or aixed at its upper end to a spacing member |03, the upper-end of this hollow spacing member |93 resting against the lower face of the end of the member 45 and being held thereto by means of bolts |94. The platform |02 is likewise secured to the lower end of the sleeve member |0| by bolts |05, this arrangement being such that the parts are held in xed relation and supported from the bed through the. stationary member 45 and the bolted connections referred to. v

The passages 95 and 95 through whichrthe adjusting bolt 96 passes through the lower end 5| of the lower piston and the head of the air pressure or cylinder space 60 in the member 45 are provided with suitable packings, illustrated conventionally. And the spacing member |03 is hollow so that the adjusting bolt 96 passes theree through and is freely movable, axially, therein but is keyed to |03, as shown at |06, against rotation.

Carried upon the platform |02 of each cushion mechanism is an adjusting motor I0, shown particularly in Figs. 2, 4, 5 and 6, the drive shaft of said motor having a worm ||2 thereon which extends through the wall of the member l0 lill, as best illustrated in detail in Fig. 6 and meshes with a worm gear H3 formed in the periphery of the nut |00. Rotation of the motor, through the intermeshing worm ||2 and gear H3, causes corresponding rotation of the nut [09 and this in turn causes corresponding ele'- vation or lowering of the adjustable bolt 96, and the stop Si may thus be positioned to limit the amount of -upward travel of the movable piston, as desired. A solenoid brake is shown diagrammatically at H5, which operates upon a brake drum H6 (see Fig. 6) so that extreme accuracy of adjustment of the stop 9'| may be secured.

The construction of this brake is shown, somewhat diagrammatically in Fig. 18, the brake being held normally closed by the spring |I'| so that the brake is on at all times when the adjusting motor is not operating. The solenoid I8 is in circuit with the adjusting motor so that as the motor is energized the solenoid is likewise energized to n'iove the operating arm H9 against the spring and release the brake shoes |20 so that adjustment may be eiected. And likewise as soon as the circuit to the motor is broken the solenoid is correspondingly deenergized and the spring instantly applies the brake so that the extreme accuracy of adjustment of the stop 91 may be secured as referred to.

In theuse of air cushion mechanisms heretoforeit has been the usual practice to compensate for variations in the effective stroke of the' air cushion piston, to meet the varying types of dies and operating conditions, by using pins of different lengths, with the length selected to meet the conditions involved. For example, a draw of four inches would require pins of diierent length from a draw of six inches; In such mechanisms the pistons would be forced down a distance equal to the length of the draw, but in all such operations the air cushion piston would be at the top of the cylinder and the cylinder full of pressure airwhen the air cushion becomes effective, and on the upstroke of the upper die the piston would rise to the top of the cylinder. By means of the present invention this same mode of operation can be carried out if desired, by adjusting the stop 9'! so that the plate 40 will always be carried to its upper dead center position by the pressure air. However, in such mode of operation the cylinder spaces would be lled with air to the maximum capacity thereof at the beginning of the operation and more or less air Would be forced back into the surge tank depending upon the depth of the draw. Also in mechanisms of this character as heretofore used it has been the usual practice to provide lock mechanisms. constructed with a desire to cause them to operate with extreme accuracy so that when the piston reaches the bottom of its stroke, as the die completes the forming operation, it should be locked and prevented from moving upward even a tiny fraction of an inch to follow the .piston on the upward portion of its cycle as, obviously, even movements of a small fraction 0f an inch with the pressures available in the air cushion,

could readily distort and deform the metal so as to ruin it for practical purposes. In locks of this, character, involving mechanical hold-down mechanisms, it has been the usual practice also to cause some slight lowering of the piston below the position corresponding to lower dead center, and to lock it in that lowered position until it is desired to be released, in order to make sure that no adverse results might ensue. And such mechanisms have included hydraulic or pneuformed so that it will restrict upper travel of the piston and confine the movement of the piston to the lower portion of its possible over-al1 length of travel. In other words, assuming that the structure as disclosed is of such dimensions that the maximum over-al1 draw permitted by the air cushion is desired and this draw is eight inches, this would mean that the parts should be so proportioned and positioned that at the beginning of the draw the stop 91 would be adjusted to its uppermost position and the pistons and plate 40 would likewise be in uppermost position and the wall 50 guiding the extension 42 would be of such dimensions that at the end of the eight inch draw the lower end of the lower piston head I would be pressed to be very close to the bottom of the piston space 60 and the upper piston head 4l equally close to the upper end of the part 45. Very satisfactory results are attained with the parts so proportioned and positioned that in this lower dead center .position the piston heads are spaced ab'out one-eighth oan inch away from their respective stationary end walls. As shown in Fig. 2 the mechanism is arranged for a draw approximately half the maximum possible draw. and 'therefore the stop 91 has been positioned sothat the upward travel of the piston is limited and the operative stroke of the piston is effective only through a limited lower portion of its possible path of travel. Y Assuming that the press requires a 3% inch depth of draw, the stop 91- would be so arranged that the lower face of the piston head 5l would be approximately 4 inches from the opposing face of its air pressure space 60. And as the press operated, after a predetermined angular portion of its downward travel the pins 36 would be forced down to exert downward pressure upon the plate 40 and force the piston downward, and the maximum travel of the piston would be limited to 37/8 inches and it would then be pressed to within one-eighth of an inch of the Ibottom of the cylinder at the end of its stroke. By means of the arrangement and construction of this invention, and the operation of the controls associated therewith, it is therefore possible to include within the air pressure spaces 60 and 6I only that amount of air which is required for the stroke of the piston, and also to provide that at the bottom of the piston stroke substantially all of the air will be forced out of the two pressure spaces l60, Bl back into the surge tank, leaving in each of those spaces only the small amount of air represented by the one-eighth inch clearance ab'ove referred to.

Utilizing the construction above described, and the controls associated therewith, the solenoid operated valves can be so actuated that as the slide approaches adequately to the bottom of the stroke the small space below the pistons willv be disconnected from the surge tank and at the same time this space will be connected to atmosphere to exhaust such small amount of pressure air as remains in this one-eighth inch clearance. Because of the very small amount of air in the clearance below the two pistons this pressure air can thus be substantially instantaneously exhausted to atmosphere, Within the brief interval corresponding to the small travel required to carry the movable die also to completion of the stroke, and the weight of the piston and parts supported thereby will cause it to drop and prevent any possible upward movement of the piston until the controls are further actuated to readmit pressure air from the surge tank to the cylinder spaces 60 and 6|. In operation the piston would be allowed to remain in this bottom position, somewhat below the lowest position' of travel of the piston during the work stroke, and pressure air would be re-admitted at a proper time in the cycle of operation as the slide moves toward upper dead center, the position in which it will ordinarily be automatically stopped, by the use of a rotary limit switch such as generally used with such presses yand illustrated'diagrammatically and hereinafter described, so-that the air cushion mechanism will thereupon act as a lift-out-to force the formed metal oi of the male die and permit of its ready removal as the slide moves to the upper position where it is automatically stopped. During such period lof operation, with both pressure spaces 6U and 6l connected through the solenoid operated valves to the surge tank, or to exhaust to atmosphere, the turn plug '86 is in the position shown in Fig. 8, so that pressure air may readily ow to and from the pressure' spaces 60 andl and the surge tank.

When it is desired'to'luse th mechanism merely as a lift-out, in an "ordinary stamping*,opera-w tion, the turn plug 8Gfispositioned as shown in Fig. 9 so that the upper pressure space '6| is at all times during operation of the press connected tothe atmosphere'and.disconnected fonr the surge tank, while'the lo'wer pressure space 60 can be connected lthrough the branch 11 and pipe 16 and solenoid operated valves tothe surge tank or exhausted to the atmosphere las described. The mechanism being thusl set,'n'o pressure air is admittedinto 'the space 6|",'and pressure air is admitted into the space llonly after the stamping operation is completed and while the die is on its upper stroke and at such proper time in the cycle that sumcient pressure will be exerted against the piston head 5l to raise the piston and cause it to actuate the ring 25 as a ufr-out ring.

Fig. 10 shows, diagrammatically, the cycle of operations when both spaces 60 and 6l are utilized, the actuation of the valves to cause the desired sequence of operations in accordance with the cycle of operation of the press being controlled by a switch, which may be suitably actuated from the reciprocating slide or from a rotary shaft or gear causing actuation thereof, and therefore is operatedin properly timed rrelation with the cyclev of the press to effectuate properly timed actuation of the control switches, etc. switch in that it initiates and limits the several periods of positioning of the valves, and is hereinafter for purposes of description referred to as a, limit switch although it ispreferably composed of rotary, and adjustably positioned cams, and might be more properly referred to as an adjustable cam switch. The switch is illustrated diagrammatically in Fig. 1 by the numeral |25, being mounted so that rotary motion is imparted thereto through a sprocket and chain drive indicated generally-the sprocket chain |26 being shown diagrammatically as carried by the drive shaft |21 which causes reciprocation of the upper slide,l

'I'his switch is'thus analogous to a limitv proper timing with the cycle of the press by the chain. The wiring diagram for this rotary limit switch is shown in Fig. 14. This switch is oi suitable cam construction, comprising a plurality of cams adapted to close contacts at predetermined points in its cycle of operation. It is believed unnecessary to show the construction in detail, but one of the cams |25' and one of the contacts operated thereby and designated generally by the numeral |29 is shown diagrammatically in Fig. 17, the remaining cams being carried on the same shaft and having proper angular positioning to cause opening and closing of the contacts and circuits carried thereby, as described.

In the drawing operation, with the pistons properly adjusted as to depths of draw-e. g., in the position illustrated and utilizing approximately half the maximum draw-as the starting button |30, Figs. 1 and 14, is pushed a clutch will be engaged so that the driving mechanism will be clutched up to be driven from a y wheel |3| which is in turn driven from the motor |32. As shown the two-way solenoid operated valve 68 is so constructed that when the circuit to the solenoid |33, Fig. 16, is open and it is deenergized the valve member |34 is so positioned that the inlet 61' and outlet 69 of the valve are both open and so that the interior of the surge tank is freely connected by way of the pipe 61 through this two-way solenoid valve to the pipe 69 which in turn' leads to the inlet of the three-way solenoid valve. And, conversely, when the circuit through the solenoid is closed and it is energized it moves the valve member so that it is in'its closed position with respect to the inlet from the surge tank but the outlet is freely open to the pipe E9. These results are attained when the valve member is held open under spring pressure and closed when the energized solenoid overcomes the 'spring-the spring |35 which surrounds the valve stem resting at one end against the valve stem packing and at the other end against an adjustable cap or stop by means of which the distance of the valve |34 from its seat when in open position may be adjusted. As shown the solenoid is deenergized and the main spring |38 then pushes the operating lever |31 up and the valve member |34 is also pushed up by its own spring to connect the inlet l' and the outlet 69. Very satisfactory results are secured, especially in higher speed presses, if the extent of closure of the inlet port of this two-way solenoid valve is made adjustable and so set that the valve does not completely close when the solenoid is energiz'ed, as in this way the speed of the cylinder return may be controlled more accurately. The three-Way solenoid valve lil, likewise, is so constructed that when the circuit through the solenoid is open and the solenoid deenergized the inlet, |39, of the valve, which is connected to the pipe 69, and the outlet |40, which is connected to the pipe 15, are open and the exhaust |4| is closed so that air can pass freely between the air cushion mechanism and the surge tank through the pipes 15, and 69 and the two solenoid valve mechanisms 68 and 10; and when the circuit is closed so that the solenoid of this three-way valve l0 is energized the inlet will be closed cutting off connection with the surge tank and the outlet will be connected to exhaust so as to permit the exhaust of the small amount of air remaining in the pressure chambers 60 and 8| as the drawing operation is completed. As shown, somewhat diagrammatically, two

sprlng pressed valve members |42 and |43 are provided within the chamber |44 to which the pipe is connected. The valve has also two passages, one of which is connected to the inlet port |39 and is controlled by the valve member |42 and the other of which is connected to the exhaust port i4! and is controlled by the valve member |43. As shown the solenoid is deenergized and the spring |45 pushes the operating lever |46 up so that the valve |42 is pushed down into open position against the resistance of its own spring while the valve member |43 is pushed up by its o'W'n spring to close of.F the chamber |44 from the exhaust |4I. When the solenoid is energized the positioning of the valve members |42, |43 is reversed.

The specific construction of the limit switch is not thought necessary to disclose but it is illustrated diagrammatically in Fig. 14, where its circuit controlling elements are shown diagrammatically in connection with the wiring diagram for the controls and operating mechanisms of this invention. This switch comprises a plurality of cams rotatably adjustable on a drive shaft so that they may be shaped and positioned for angular adjustment to give properly timed opening and lclosing of the solenoid circuits at. the desired times in the cycle of the press. The shaft is operated by means of the sprocket and chain arrangement described. As shown four cams are provided, ydesignated generally by the numeral |25'; .in Fig. 14 and each of these cams is shown in flat projection and designatedrespectively by the number LS-I LS-2, LS--3 and LS-'4, the shaded portion on each flat projection indicating that part of the cam which holds the corresponding contacts, or switch, closed, and the unshaded'portions the angular period during which the solenoid circuits are not energized. Of the four controlling cam members thus shown numbers LS-I and ILS- 2 are utilized for controlling the air cushion operations during a cycle of the press when a drawing operkation is ,being performed as'. diagrammatically "illustrated in Fig. 10, LS-S and LS--4 being used for a stamping operation When the air cushions are used merely'for lift-outs, as hereinafter explained.

The member 95 having been adjusted for the depth of draw required and the die members and pins` having been properly positioned. the starting button 3D, shown diagrammatically in Fig. 1, and also diagrammatically in Fig. 14, is pushed to start the cycle of operations, At this time pressure air fills the spaces 50 and 3|, and each plate and the pressure pins are in the uppermost position permitted by the stop 81 and supporting the draw ring and the sheet of metal to be formed. The upper die is at approximately upper Idead center and held against movement by the brake and with the clutch out at the time the starting button is pushed, this position in the cycle of operations being indicated by the 0 mark in the diagrammatic cycle illustrated at the top of Fig, 10. As the limit switch rotates and reaches position No. 1 both the two-way and the threeway solenoid valves are deenergized, the threeway valve having already been deenergized at position No. 3 of the previous press cycle as hereinafter described, as shown in Fig, 14, and therefore'the interior of the surge tank is placed in wide open connection with the pressure spaces and 6| and as the die moves down in the cycle of operation the air within the pressure cylinders is caused to surge back through the several the valve members |42, |43 are moved to reversed position from that shown in Fig. 15, and the surge tank is shut off by the closed valve member |42 and the pressure space within the air cushion is connected through the outlet valve |43 and exhaust to the atmosphere to permit escape of the small portion of air left in the pressure spaces andA to permit the pistons and pins to sink to the bottom Where they will remain completely inoperative with -respect to the drawn member. In this Way all o f the advantages ofA the moreintricate and complicated and involved hold-down and locking devices heretofore used are retained with a very simple mechanism which may be easily and accurately controlled. The pressure piston and associated parts will remain in this lowered, inoperative, position until the limit switch in the cycle of operation reaches position No. 3, on the upstroke of the movable die. The two-way solenoid valve will then be energized and its valve member moved to closed position and its outlet left open, and at the same time the threeway solenoid valve will be deenergized so that its inlet and outlet will be re-connected and 'it5.ex' haust closed. vAs a kresult of the valve |34 being s o adjusted that it will not completely close pressure air will flow from the surge tank through the partly closed inlet of the two-way valve andl will build up air pressure `in the air cushions so as to raise the pistons and pins and the draw ring to move the formed metal oi of the male die, without `any danger of a suiciently severe shock to deform the metal. When operating in the usual manner, the press Will be automatically brought to a stop as the die reaches approximately upper dead center, the automatic stop mechanism functioning then to unclutch the die operating mechanisms from the drive motor and at the same time apply a brake to insure stopping the press at approximately the top of its stroke.

By the use of the air cushions and controls as thus described ordinary drawing operations can be performed, and also by proper selection and spacing of the pressure pins localized pressures can be exerted in desired portions of the dies, and reverse draws can also be satisfactorily performed-all in the manner of operation and with the advantages described.

If it is desired to use the air cushions merely for lift-out, as when the press is used to perform stamping operations, then the limit switch will be set so as to follow the cycle of operations shown in Fig. l1 In this stamping operation, as stated above, the valve member 86 is set so that no air is admitted to the pressure space 6| and air is admitted to the pressure space 60 only during the latter half of the cycle. During such operation the cams LS-3 and LS-4 are eiective and as shown by Fig. 11, the upper pressure space 6| is at all times connected to the atmosphere. After,

the press moves to lower dead center, indicated by 180 in Fig. 11, to complete the stamping and starts on the return upstroke and reaches position No. 4 the solenoids for both valves will be deenergized so that the inlet and outlet ports of the two-way solenoid valve will be open, the

inlet and outlet of the' three-way solenoid: will be connected ,and the' exhaust 0f that 16 three-way valve will be closed. As a result pressure air will pass from the surge tank into the pressure space 6D, the effective area of the piston 5| being sufcient to lift the parts and eiect lift-out of the stamping. When the press reaches position No. 5 shortly before' upper dead center the two-way solenoid valve will remain deenergized with the inlet and outlet open; but the three-way solenoid valve will be energized so that the inlet valve member |42 will be closed and thespace |44 connected to the exhaust MI to thus permit the escape of air from the space to the atmosphere and permit the piston'and the parts supported by it to sink to lowermost position so as to be out of the way for the succeeding work operation. The `valve 56 has been independently set, of course, so that the space 6|) is completely cutoff from the surge tank and kep-t 'open to exhaust.

For purposes of effecting actuation of thefsolenoid control valves and the functioning of the air cushions in the manner above described cir.- cuits and switches are provided, as illustrated in the wiring diagram forming a part of Fig. 14. As stated the adjustable cam members of the limit switch |25 are shown in flat projection as in..

dicated by the numeral |25. with the angular travel during one complete cycle being indicated by the degree marks, 0 and 360 representing upper dead center and 180 lower dead centerin the stroke of the prees. As illustrated threephase current is supplied to this part of the press mechanism through a three-wire system, this three-phase current being preferably `44|) volts. This whole electric wiring system is provided with a switch |50 for opening and closing the circuit to these control mechanisms. .The adjusting motor I0 is a three-phase motor and is connected as such to the three-wire system. Also as shown two -of the wires are connected through the twoway solenoid valve 68, actuated by means ofv a control relay marked CR/-g the three-way solenoid valve TB likewise being connected to these same two wires through a control relay marked CR-2. And to provide an integrated built-in wiring system for eiecting the desired controls a transformer |55 is provided for stepping down the higher voltage of the three-wire circuit to the lower 110 volts which is utilized in the circuits for controlling the several switches and solenoid valve relay controls, this circuit being generally designated by the numeral |55.

With. the switch |56 opened, and so with the circuit open the air cylinders will operate in conventional manner with air pressure on pistons at all times, providing plug d cf valve is in position shown in Fig. 8. That is both solenoids will be deenergized and therefore the air spaces 68, 6| will be in open surging connection with the surge tank 65. ABut with the switch |50 closed the cycles of operation above described will be secured for drawing and lift-out or for lift-out only according to the setting of the control switches.

Located in a convenient place for the operator is a push button station designated generally by of the member 96 is secured, whereby the solenoid valves are controlled through the cam members vLS--I and LS-Z for a drawing operation, in accordance with the diagrammatic showing lof lOvand to causetheair cushions to function 17 as above described; and through the cam members LS-3 and LS-4 to eiect control of the air cushions in accordance with the diagrammatic showing of Fig. 11 as above described.

The switch |5| may be set for the position marked Adj., or adjust, in which position it is set so that operation of the adjusting motor ||0 can be effected. As shown on the push button station., the two lower buttons are marked Up and Down and these buttons control the correspondingly marked switches in the lines |65 and |66, in which are the relays |81 and |68 respectively, which relays actuate a reversing switch controlling the adjusting motor ||0 to cause that motor to operate to raise or lower the member 96. The two push buttons which are marked Up and Down on the push button station |50 are conventionally constructed so that each button must be pushed to close the circuit it controls and when the pressure is released the switch controlled by it springs open. In order to effect operation of the adjusting motor 0 in either direction, therefore, the switch |6| is rst moved to the adjusting position which cuts out the controls for the solenoid valves and cuts in the circuits |65 and |66. However these circuits will be effective upon the motor only as the respective relays |61 and |68 are actuated and this is accomplished by pushing the proper Up" or Down button on the push button station |60. When the Up button ispushed this will close the circuit through the relay |61, the circuit through relay |68 being open, and when the Down button is pushed the reverse connection is secured. The switch |6| therefore being placed in the adjustment setting, and the proper button pushed the motor 0 will operate so long as that condition is maintained. It is necessary to hold Up or Down" button to continue operation of motor, releasing of button stops motor. When the motor is in operation, the brake is energized and held open. When current is off motor, current is also orf brake and the brake is applied by spring.

With the switch l'l moved to off position the whole of the circuit designated generally |55 is dead and inoperative vand the air cushions are connected to the surge tank and if this is connected the pistons would move down during downstroke of the press against the pressure air and up during upstroke of the press under the pressure air, this being somewhat in the conventional manner and highly objectionable in actual operation in the absence of some of the highly complicated hold down or locking mechanisms heretofore referred to. And with the advantages of this invention such operation would not be utilized except under some unusual operating conditions which might possibly arise and make this type of operation desirable. When it is desired to have the air cushions automatically controlled either for the drawing operation or a mere liftout, as in connection with a stamping operation, the circuits marked LS-|, LS-2, LS-3 and LS--ll are controlled by means of the cams in the limit switch |25, and in accordance with the diagrammatic showing in this Fig. 14. All of' the cams rotate during operation of the press but by operation of the push buttons marked Draw and Lift, on the push button station |69, the proper circuits for controlling the solenoid operated valves to secure the operations illustrated in Fig. 10 and described in connection therewith or the operations illustrated in Fig. 11 and described in connection therewith can be secured. As shown` diagrammatically the buttons marked Draw and Lift are so connected that when the Draw button actuates the switches connected therewith to close the lines marked LS-l and LS-Z it will also automatically actuate the switches controlling the lines LS-3 and LS-ll to open those lines and prevent the flow of current therethrough. Furthermore in order that these controls may be effectuated through the switch i 25 the switch |61 should be moved to the position marked Auto. which indicates a setting for automatic operations as the press goes through its various cycles. With the switch |6| in this Auto. position and with the Draw button actuated to close the circuits LS-i and LS-2., the position illustrated diagrammatically in Fig. 1.4, the circuits will automatically be closed through the switches illustrated diagrammatical- 1y and numbered |10 and |1|, and as shown, as positions- 1, 2 and 3- are reached during the cycle of the press, the control relays CR-l and CR--2 for the solenoid valves 68 and 10 will be opened and closed in the sequence above described to give the setting of the valves illustrated in Fig. 10, and the functioning which results therefrom.

Likewise when the Lift button is pushed, to close the two switches marked Lift in lines LS--3 and LS--4, this will automatically open the twoDraw switches in lines LS-I and LS-2 and during the cycling of the press this in turn will cause actuation of the switches |12 and |13 so as togive the positioning of the valves illlustrated in Fig. 11, and the functioning described in connection therewith.

As adjustment of the member 96 should take place when all pressure air is exhausted from the spaces 60 and 6|-, so that the pressures will not affect the operation of the motor H0, another push button switch is provided which is designated by the numeral |80, which is so connected that automatically it will move the switches |10 and |1|` so asto place them in a position corresponding to position No. 2 of Fig. 10, this switch being manually controlled at any time to effect such setting of the solenoid control valves. When this manually controlled switch is thus set, with the switch |6.| in AdjJ position it will energize the three-way solenoid valve thus opening it toexhaust as in position No. 2 in Fig. 10, the switch being shown in dotted lines in this adjusted position and indicated by the numeral 220, and the circuit being indicated by the numerals 22|, 22| to CR-2.

In order to @permit of readily adjusting the air cushion for any desired depth of draw, and to give the minimum safe operating clearance of approximately one-eighth of an inch as described and thus to-minimize the amount of pressure air exhausted to the atmosphere, suitable gages are provided. The skirt 43 of each movable or piston member of each air cushion has connected thereto a downwardly extending rod 200 to which is attached -an arm 20|, from which an upwardly extending gage rod 202 extends to terminate opposite agage member 203, the details of which are shown in Fig. 13. There is one of these gages for each air cushion, one being shown at each side of the press in Figs. 1 and 2. As shown, the gages are marked in inches for a maximum 8 inch draw, and the members 200, 20| and 202 are adjustably interconnected, by means of threaded connections' with lock nuts as shown, so that the upper end of each rod 202 may be adjusted so as to be positioned opposite the markings on the gage' to' indicate accurately the 'exact elevation side with a slot 209 through which extends a pin 2I0, which is threaded or otherwise secured in the adjustable member 96. The outer end of this pin 210 is connected to a flexible cable,

such as a Bowden wire 2l I, which passes downwardly through a passage in the housing for the adjusting nut |00 and. then upwardly where it connects to the Alower end of the gage member 212, which cooperates with a double faced gage plate designatedgenerally by the numeral 2|3. As the adjusting member 96 moves up or down, as the adjusting nut |00 is turned, the upper end. of the gage member l2I'2 becaused to move correspondingly. As shown in Fig. 12 the gage 'face 0n the right is marked to indicate the length .of travel of the plate 40 during a drawing operation-or the .length of pin plate strokeand the gage face on' the: left is marked to indicate the distance'of the plate 40 from the bottom of the bolster-or distance from pin plate to bottom of bolster. In this way the exact position of the pistons with reference to the stationary member 45 may be determined so as to give sufficient clearance at the end of the 4Working stroke of the die4 so thatlthe parts will not come in physical contact and the desired very small final clearance maybe provided for the spaces 60 and 6|. Likewise the distance of travel of the plate 40 can be accurately determined to make sure that it has 'its proper relationship to the required eiective distance of applied pressure during the working strokes-A And also the distance of the plate lm from the bottom of the bolster may .be determined so that pins of proper length may be readily utilized and also to make sure that suicient travel is permitted to effectuate the lift-out operation.

While the method herein described, and the forms of apparatus for carrying this method into eiect, constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to this precise method and forms of apparatus, and that changes may be made in either Without departing from the scope of the invention which is dened in the appended claims.

What is claimed is:

1. For use in a press of the character described, comprising relatively movable die carrying members and operating means `for eecting work movement of the dies carried by said members, control means for the die operating means constructed for effecting controlof the cycles of operation and for effecting predetermined points in the cycle 0f operation, and in combination. an air cushion mechanism including a, cylinder member containing a pressure space and a. cooperating piston member, means securing one of said cylinder and piston members in xed relation with respect to one of said die carrying members, means supporting the other of said cylinder and piston members for movement in one direction with respect to said xed member under pressure air admitted to said pressure space and for movement in the other direction with respect to said xed member under pressure exerted thereon by the dies during working movement, adjustable means for limiting said relative movement of said cylinder and piston members under the iniluenceof the pressure air to a travel slightly in excess of the travel caused bythe working movement of the dies carried by said die carrying members, and means for adjusting said limiting means to accommodate dies constructed for diierent depths of draw.

2. For use in a press 0f the character described, comprising relatively movable die carrying members and operating means for electing work movement of the dies carried by said members,

control means for the die operating means constructed 'for effecting control of the cycles of operation and for effecting predetermined sequential controls in each cycle of operation coordinated with predetermined points in the cycle, and in combination; an air cushion mechanism comprising a cylinder member containing a pressure space and a cooperating piston member, means providing a connection between said pressure space anda source of pressure air, means providing a connection between said pressure space and the outside atmosphere for exhaust purposes, valve means controlling each of said connections, means securing one of said cylinder and piston members in fixed relation with respect to one of said press members, means supporting the other of said cylinder and piston members for reciprocal movement upwardly with respect to said fixed member under the inuence of pressure air Aadmitted to said -pressure space and downwardly under the pressure exerted thereon by the diesj during working movement, adjustable means for limiting said relative movement 0f said cylinder and piston members under the iniluence of pressure air to a travel slightly in excess of the travel caused by the working movement of the dies carried by said die carrying members, and means for adjusting said limiting means to accommodate dies constructed for different depths of draw, said control means includingmeans operative upon said valve means at a predetermined point in each cycleof said press to' disconnect said pressure space from exhaust and connect it to said source of pressure air and at a second predetermined point in each movementl of the dies carried by said members,

control means for the die operating means constructed for effecting control of the cycles of operation and for eiecting predetermined sequential controls in each cycle of operation coordinated by pressure air admitted to said pressure space and in the other direction under the pressure exerted thereon by the dies during work movement of the dies, a threaded axially movable member having a stop cooperating with said piston to limit its movement by pressure air relative to the cylinder, a rotatable adjusting nut threaded on said movable member and a motor in driving connection with said nut, and means for controlling operation of said motor to set said stop to limit such movement of the piston toa distance slightly more than the depth of draw of the dies as eiective upon said cushion member, whereby at the end of the drawing stroke the piston member will occupy substantially all of the `pressure 21 space except for a slight predetermined working clearance.

4. For use in a press of the character described, comprising relatively movable die carrying members and operating means for eiecting work movement of the dies carried by said members, pressure pins, control means for the die operating means constructed to eiiect complete cycles of operation of the press and for effecting predetermined sequential controls in each cycle of operation coordinated with predetermined points in the cycle, and in combination; an air cushion mechanism comprising a cylinder member containing a pressure space and a cooperating piston member carrying a pressure plate, said piston being guided in the cylinder and movable upwardly by pressure fluid admitted to said pressure space and movable in the other direction under the pressures exerted on the movable piston by the pins during work movement of the dies, adjustable means for limiting upward movement of the piston under the inuence of the pressure fluid in said pressure space, said adjustable means being constructed for positioning to limit such movement t a distance slightly more than the downward movement of the piston during work movement of the dies, and control means constructed to be operated by the press for connecting and disconnecting the pressure space from the source of pressure air and for exhausting the pressure air remaining in said space at the bottom of the drawing stroke of the press, the construction being such that at the end of the drawing operation the piston will occupy substantially the entire pressure space except for a slight operating clearance and the pressure air thereupon exhausted from said diminished space will be only slight in amount.

5. For use in a press of the character described, comprising a bolster plate, a die member mounted thereon and a die member reciprocable relative thereto, pressure pins, operating means for eiecting work movement of said dies, and control means for said operating means to effect complete cycles of operation of the press, and in combination; an air cushion mechanism comprising a cylinder containing a pressure space and a cooperating piston, a pressure plate carried by the piston adapted to support the pressure pins to transmit pressure between the piston and die parts during work movement of the dies, a guide portion carried by said piston and cooperating guiding walls extending from said pressure space, said guide and cooperating guiding walls of such extent as to withstand the variable pressure loads incident to variable work operations, means for limiting the upward movement of the piston under pressure air admitted to the pressure space, said means being adjustable to limit such upward movement to a selected distance slightly more than the downward movement of the piston duringa work movement of the dies, means for connecting said pressure space to a source of pressure fluid, means for disconnecting said pressure space from said source of fluid and concomitantly connecting it to exhaust, and control means adapted to be operated by the press for eiecting predetermined sequential controls in each cycle of operation, said control means being constructed to admit pressure fluid to the pressure space sufficient to lift the weight of said pistonA and any parts carried thereby but to yield under drawing pressure exerted upon the piston from the dies during drawing action, and said control means being also effective at a predetermined point in the cycle of operations approximately corresponding to lower dead center to disconnect the pressure space from the source of pressure fluid and connect said pressure space to exhaust; and the construction being such that the piston occupies substantially the entire effective pressure space at lower dead center leaving only a slight operating clearance in said pressure space and only a small amount of air therein to be exhausted at lower dead center.

6. For use in a press of the character described, comprising a stationary member and a member reciprocable relative thereto to receive cooperating dies, operating means for effecting work movement of said members and dies, control means for said operating means to eiect complete cycles of operation of the press, and in combination; an air cushion mechanism comprising a cylinder containing a pressure space and a cooperating piston guided therein, means for connecting said pressure space to a source of pressure iiuid, means for disconnecting said pressure space from said source of pressure fluid and concomitantly connecting it to exhaust, means constructed for adjustment to limit upward movement of the piston under the pressure air admitted to the pressure space to a selected distance slightly more than the downward movement of the piston during a work movement of the dies, control means adapted to be operated by the press for effecting predetermined sequen-v tial controls in each cycle of operation, said control means being constructed to admit pressure fluid to the pressure space to lift the weight of said piston and any parts carried thereby but to yield under drawing pressure exerted upon the piston from the dies during drawing action, and said control means being also effective at a predetermined point in the cycle of operations approximately corresponding to lower dead center to disconnect the pressure space from the source of pressure iiuid and connect said pressure space to exhaust and for maintaining such connection to exhaust until a predetermined point in the upstroke of the press-cycle and then to reconnect such pressure space to the source of pressure and close exhaust, and the construction being such that the piston occupies substantially the entire effective pressure space at lower dead center leaving only a slight operating clearance in said pressure space and only a small amount of air therein to be exhausted at lower dea-d center and to permit the piston and parts supported thereby to move down under the weight thereof below lower dead center and to remain in such lowered position until said predetermined point in the upstroke of the cycle is reached.

7. A press of the character described, comprising relatively movable die carrying members and operating means for eiecting work movement of the dies carried by said members, control means for the die operating means constructed to eiect complete cycles of operation of the press and for effecting predetermined sequential controls in each cycle of operation coordinated with predetermined points in the cycle, and in combination; an air cushion mechanism comprising a cylinder member containing a pressure space and a cooperating piston member guided therein and movable upwardly by pressure fluid admitted to said pressure space and movable in the other direction under the pressures exerted on the movable piston by the dies during work movement of the dies, and adjustable means for limiting upward movement of the piston under the inuence of the pressure uid in said pressure space and control means therefor, said adjustable means being constructed for positioning to limit such movement to a distance slightly more than the depth of draw of the dies effective upon said piston, and means actuated by said control means for connecting and for disconnecting the pressure space from the source of pressure air and for exhausting the pressure air remaining in said space at the bottom of the drawing stroke of the press, the construction being such that at the end of the drawing operation the piston will occupy substantially the entire pressure space except for a slight operating clearance and the pressure air thereupon exhausted from said diminished space will be only slight in amount.

8. A press of the character described, comprising a stationary member and a member reciprocable relative thereto to receive cooperating dies, operating means for effecting work movement of said members and the dies carried thereby, control means for said operating means to effect independent cycles of operation of the press, and in combination; an air cushion mechanism comprising a cylinder member containing a pressure space and a cooperating piston member guided therein, means for connecting said pressure space to a source of pressure fluid, means for disconnecting said pressure space from said source of pressure uid and concomitantly connecting said pressure space to exhaust, and control means operable by the press for effecting predetermined sequential controls in each cycle of operation coordinated with predetermined points in the cycle, said control means being constructed to admit pressure uid to the pressure space to exert pressure sufiicient to lift the weight of said piston and any parts carried thereby but to yield under pressure exerted upon the piston from the dies during drawing action, and said control means being also effective at a predetermined point in the cycle of operations approximately corresponding to lower dead center for disconnecting the pressure space from the source of pressure fluid and connecting said pressure space to exhaust, and adjustable means for limiting the upward movement of the piston under the pressure air admitted to the pressure space during the drawing portion of the press cycle, said means being constructed for adjustment to limit such upward movement to a distance slightly more than the depth of draw of the dies eiective upon said cushion member, and the construction being such that at lower dead center the piston occupies substantially the entire eiective pressure space and will leave only a slight operating clearance in said pressure space and only a small amount of air remains therein to be exhausted at the end of the drawing operation.

9. In a press of the character described, comprisinga stationary member and a member reciprocable relative thereto to carry cooperating dies, operating means therefor, control means for said operating means to eiect complete cycles of operation of the press, and in combination; an air cushion mechanism comprising a cylinder containing a pressure space and a cooperating piston guided therein, means for connecting said pressure space to a source of pressure iluid, means for disconnecting said pressure space from said source of pressure uid and concomitantly connecting said pressure space to exhaust, control means operable by the press for effecting sequential controls at predetermined points in each cycle of operation, said control means being constructed to admit pressure uid to the pressure space to exert controlled pressure to lift the weight of said piston and any parts carried thereby but to yield under pressure exerted upon the piston from the dies, and said control means being also eiective at a predetermined point in the cycle of operations approximately corresponding to lower dead center for disconnecting the pressure space from the source of pressure fluid and connecting it to exhaust and for maintaining such connection to exhaust until a predetermined point in the upstroke of the press cycle and then to disconnect the pressure space from exhaust and reconnect it to the source of Supply of pressure fluid, adjustable means for limiting upward movement of the piston under the pressure iiuid admitted to the pressure space during the press cycle, said means being constructed for adjustment to limit such upward movement to a distance slightly more than the depth of draw of the dies eiective upon said cushion member and the construction being such that at the end of the drawing operation the piston will occupy substantially the entire eiective pressure space and leave only a slight operating clearance in said pressure space with only a small amount of air remaining therein to be exhausted to permit the piston and parts supported thereby to move down under the weight thereof below lower dead center of the movable die and to remain in such lowered position until said predetermined point in the upstroke of the cycle is reached and to cause the piston then to move upward under the pressure fluid to eject the formed article.

10. Mechanism of the character dened in claim l in which the cylinder has two separated pressure spaces and the piston member two corresponding pressure responsive portions, means for connecting each of said pressure spaces to a source of pressure uid and means for disconnecting one of said pressure spaces from the source of pressure supply and for connecting it to exhaust without aiecting the connection between the other pressure space and the source of pressure fluid.

1,1. Mechanism of the character defined in claim 1, in which the cylinder has two pressure spaces and the piston member two corresponding pressure responsive portions each operable in its own pressure space, means for rendering one of said pressure spaces and its piston portion inoperative, and means for connecting the other pressure space to a source of pressure fluid and means for connecting said other pressure space to exhaust, and control means actuated at predetermined points in a cycle of press operation and operable to disconnect said other pressure space from the source of pressure uid and connect it to exhaust during the work forming part of the press cycle to permit the piston and parts supported thereby to move down under the weight thereof below lower dead center and to remain inactive in said lowered position until after the forming operation is completed and a predetermined point further in the press cycle is then reached and then to disconnect said other pressure space from exhaust and connect it to the source of pressure uid to cause the piston then to move upward under the pressure uid to eject the formed article.

l2. Mechanism of the character dened in claim l, in which the cylinder has two separated pressure spaces and the piston member two corresponding pressure responsive portions each 0D- 25 erable in its own pressure space, one of said pressure spaces and its piston-portion being of greater area than the other, means for connecting each of said pressure spaces to a source of pressure fluid, means for disconnecting each of said pressure spaces from the source of pressure and for connecting it to exhaust, and means for disconnecting the larger or" said pressure spaces from the source of pressure fluid and for connecting it to exhaust to render it inoperative throughout the work cycle of thepress, means for connecting the smaller pressure space to the source of pressure iiuid and for connecting it to exhaust, and control means operative to connect both pres- -sure spaces to the source of pressure fluid at the same time and to disconnect both pressure spaces from the source of pressure fluid and to connect them to exhaust at the same time, and means for disconnecting the larger pressure space from the source of pressure iiuid and connecting it to exhaust and for connecting and disconnecting the smaller pressure space with the source -of pressure fluid and the exhaust in sequential operations in the cycle of the press, without affecting the connection maintained between the other pressure space and exhaust.

13. Mechanism of the. character defined in claim 1, in which the cylinder has two separated pressure spaces and the piston member two corresponding pressure responsive portions each op- .l

erable in its own pressure space, one of said pressure spaces and its piston portion being of greater area than the other, means for connecting each of said pressure spaces to a source of pressure uid, means for disconnecting each of said pressure spaces from the source of pressure and for connecting it to exhaust, and independent means for disconnecting the larger of said pressure spaces from the source of pressure iiuid and for connecting it to exhaust to render it inoperative throughout the work cycle of the press, and control means for said two first named means actuated from the press operating mechanism during a work cycle and constructed to connect ,the smaller pressure space to exhaust at the beginning of a work stroke and to admit pressure uid into said smaller pressure space at a predetermined point in the cycle upon completion of the forming operation to eect lift-out of the formed article, without affecting the connection maintained by the independent means between the other pressure space and exhaust.

14. Air cushion mechanism of the character described, for use as a self-contained unit in metal drawing and stamping presses and the like, comprising a pressure cylinder, a piston member slidable therein, means for attaching one of said cylinder and piston members to a portion of the l press, means limiting tthe maximum relative travel of said cylinder and piston, said piston including an elongated guiding extension substantially-greater in length than said maximum relative travel of said cylinder and piston, said cylinder also having an elongated 'guiding extension of a length substantially in excess of said maximum relative travel of said cylinder and piston, said piston and cylinder extensions having bearing surfaces axially spaced from each other by a distance at least as great as said maximum relative travel of said cylinder and piston and forming the primary guiding support for withstanding the variable pressure loads incident to the variable operations of the press, a pressure plate fastened to the piston for receiving and transmitting pressures and work loads between the 26 piston and the press diey and means for detachably connecting said pressure plateto said piston, whereby a standard size cylinder and piston may receive varying sized pressure plates to fit varying size pressure plate openings in varying sized presses.

15. A press of the character described comprising relatively movable die carrying members and operating means for effecting work movement of the dies carried by said members, control means for said operating means constructed to effect complete cycles of operation of the press, an air cushion mechanism comprising a cylinder containing a pressure space and a cooperating piston, pressure pins for transmitting pressure between said piston and the dies during a cycle of operation, an axial extension carried by said piston and slidable within guide walls carried by the cylinder to provide guiding lmeans constructed and of such extent as'to withstand the variable pressure loads incident to the variable work operations, means for connecting the pressure space of said cylinder to a source of controlled fluid pressure tocause upward movement of the piston, adjustable means for limiting the upward movement of the piston under the pressure fluid said means being adjustable to limit such upward movement to a distance slightly more-than the downward movement of the piston during a work movement of the dies, means operable to disconnect the source of pressure fluid from the cylinder and to connect the cylinder to exhaust at approximately lower dead center, the construction being such that the piston will then occupy substantially the entire pressure space and will immediately drop under the weight of the parts and remain below lower dead center, and means operable a't a predetermined point in the upstroke of the press for connecting the pressure space below the piston to the source of pressure iluid and disconnecting said space from exhaust to cause upward movement of said piston, and means constructed to be operated from the operating means of the press for causing said sequential actuation of the pressure fluid control means.

16. A press of the character described comprising relatively movable die carrying member and operating means for effecting movement ofy the dies carried by said members, a plurality of pressure cushions each comprising a relatively movable cylinder and piston, pressure pins for transmitting pressure between each cushion and the dies, each cushion having an adjustable member with a stop and means for adjusting to bring each stop to a predetermined point effective to limit the upward movement of the piston to a distance slightly more than the depth of draw of the dies effective upon said piston, means for connecting each of said air cushions to a source y of pressure fluid, each said means being constructed for sequential operations in a cycle of the press to connect the cylinder to the pressure fluid and disconnect the cylinder from exhaust at a predetermined point during down stroke of the dies, to disconnect the cylinder from the pressure fluid and connect it to exhaust at approximately lower dead center to permit the piston to sink under its weight and remain below lower dead center until a predetermined point in the upstroke of lthe dies and at such predetermined point to disconnect the cylinder from exhaust and reconnect it to the source of pressure uid to eject the formed article, and means operated by the press operating mechanism for ef- 27 fecting said sequential actuation of said connecting' means.

17. A press of the character described comprising relatively movable die carrying members, means for ope-rating said members and the dies carried thereby, a plurality of air cushions, each comprising'a cylinder and a piston, adjusting means for each cushion operable to limit the upward travel of its piston, means for eiecting adjustment of said piston limiting means to give predetermined limited upward travel of the piston, a source of pressure air including a surge tank and means for controlling lthe pressure therein, means for connecting said surge tank to each of said cylinders and comprising valve meansand controls therefor said controls being constructed to be effective in one position to connect the cylinder to the surge tank for air surging while holding exhaust closed, in a second position to connect the cylinder to exhaust and to disconnect the cylinder from the surge tank as .the dies reach lower dead center and at a time when the piston occupies substantially the entire pressure' space and the small air remaining will exhaust substantially immediately to permit the piston to drop below and remain below lower dead center,

and in a third predetermined position on the upstroke of the dies to disconnect the cylinder from exhaust and reconnectit to the surge tank, and means actuated from the press operating means for operating said controls in said several sequential operations.

18. A press of the character described comprising relatively 'movable die carrying members, means for operating said members and the dies carried thereby, a plurality of air cushions, each comprising a cylinder and a piston, adjusting means for each cushion operable to limit the upward travel of its piston, means for effecting adjustment of said piston limiting means to give predetermined limited upward travel of the piston, a source of pressure air including a surge tank and means for controlling the pressure therein, means for connecting said surge tank to each of said cylinders and comprising valve means and controls therefor, said controls being constructed to be effective in one position to disconnect the cylinder and surge tank and connect the cylinder to exhaust at the beginning of the down stroke of the die to permit the piston under its own weight to sink and remain below lower dead center of the die, and at a predetermined DOint in the upstroke of the die to close the cylinder exhaust and reconnect the cylinder to the surge tank, and means actuated from the press operating means for operating said controls in said several sequential operations.

19. A press of the character described comprising relatively movable die carrying members, means for operating said members and the dies carried thereby, a plurality of air cushions, each comprising a cylinder anda piston, adjusting means for each cushion operable to limit the upward travel ofthe piston, means for effecting adjustment of said piston limiting means to give predetermined limited upward travel of the piston, a source of pressure air including a surge tank and means for controlling the pressure therein, means for connecting said surge tank to each of said cylinders and comprising valve means and controls therefor, said controls comprising sequentially actuated means and an independent valve setting means and being constructed to be effective in one position. t QQnnect the cylinder to the surge tank for air surging while holding exhaust closed, in a second position to connect the cylinder'to exhaust and to disconnect the cylinder from the surge tank as the dies reach lower dead center and at a time when the piston occupies substantially the entire pressure space and lthe small air remaining will exhaust substantially immediately to permit the piston to drop below and remain below lower dead center, and in a third predetermined position on the upstroke of the dies to disconnect the cylinder from exhaust and reconnect it to the surge tank and in another position to disconnect the cylinder 'and surge tank' and connect the cylinder to exhaust at the beginning of the down stroke of the die to permit the piston under its own weight totsink and remain below lower dead center of 'the die, and at a predetermined point in the upstroke of the die to close the cylinder exhaust and reconnect the cylinder to the surgevtank, and means' actuated from the press operating'm'eans for operating said controis in said several sequential operations.

20. A press structure vof the character dened in claim 19, in which the sequentially actuated control valves are solenoid controlled and interconnected and the circuits therefor are controlled by a plurality of switches operated by cams driven in synchronism with the press operating means and comprise also hand operated switches for selectively connecting said solenoids in either of two sets of circuits, and so constructed that with the independent valve 4setting means and one -of the hand operatedswitchesin the drawing position the pressure cushions will perform the sequential operations of, claim 17, and in the stamping position will perform the sequential operations of claim 18. Y

21. A pressv of the character described comprising relatively Ymovable die .carrying members and operating means for effecting movement of thedies carried by said members, a pressure cush- -ion mechanismV comprising arelatively movable cylinder and piston, pressure pins transmitting pressure between such cushion and the dies, means for connecting thepressure space of said cushion to a source of pressure fluid, means for connecting said space to exhaust, each said means being constructed for sequential operations in the cycle of the press, and means operable by the press in its cycling and eiective upon the said cushion control means to disconnect the ,cylinder from the ,pressure fluid and exhaust to atmosphere at a predetermined point in the upstroke of one cycle of the press and after lower dead center, and to connect said cylinder to pressure air at a predetermined point in the next cycle of the press on the upstroke after lower dead center and at an angular positioning closer to lower dead center than the above specified exhaust position, whereby .the cylinder is already connected to exhaust-at the beginning of -the cycle of operation, is connected to pressure fluid l for lift-out operation after lower dead center and during the upstroke of the cycle, and is thereafter again connected to exhaust before the press in its cycle reaches upper dead center.

V22.YA press structure of the character dened in claim 17, in which the sequentially'actuated control valves are solenoid controlled and .interconnected and the circuits therefor are controlled by a plurality of switches operated by cams driven in synchronism with the press operating means. 23. A press structure of the character dend in 29 claim 18, in which the sequentially actuated control valves are solenoid controlled and interconnected and the circuits therefor are controlled by a plurality of switches operated by cams driven in synchronism with the press operating means.

24. A press of the character described comprising relatively movable die carrying members,'

means for supporting said die carrying members including a bolster plate for one of said members, means for effecting operative work movement of the dies carried by said members, a movable lift out or draw ring cooperating with one of said die carrying members, supporting pins for said draw ring movably extending through said bolster plate, an air cushion mechanism comprising a cylinder member containing a pressure space and a cooperating piston member, means carried by said air cushion mechanism effective upon the other ends of said pins, said piston being movable in one direction during die forming operation by pressure transmitted thereto from said ring through said pins and movable in the other direction by pressure air within said pressure space, adjustable means for limiting movement of said piston under the influence of the pressure air to a stroke slightly in excess of the travel caused by the Working movement of the dies carried by said die carrying members and less than the maximum distance between said piston and said bolster, the position of said piston under said pressure transmitted thereto through said pins at lower dead center of said die carrying members being spaced slightly from the opposite wall of said pressure space to leave a predetermined slight clearance, and means for adjusting said limiting means to accommodate dies constructed for different depths of draw.

25. Air cushion mechanism of the character described, for use as a self -contained unit in metal drawing and stamping presses and the like, comprising a pressure cylinder, a piston member slidable therein, means for attaching one of said cylinder and piston members to a portion of the press, means limiting the maximum relative travel of said cylinder and piston, said piston including an elongated guiding extension substantially greater in length than said maximum relative travel of said cylinder and piston, said cylinder also having an elongated guiding extension of a length substantially in excess of said maximum relative travel of said cylinder and piston, said piston and cylinder extensions having bearing surfaces axially spaced from each other by a distance at least as great as said maximum relative travel of said cylinder and piston forming the primary guiding support for withstanding the Variable pressure loads incident to the Variable operations of the press, said piston extension including an annular plate member at the opposite end thereof from the pressure responsive portion of said piston within said cylinder and substantially para1le1 to said pressure responsive portion, said annular plate member having an annular extension thereon spaced outwardly from the substantially concentric with said guiding extension on said piston, said annular extension having closed working relation with said cylinder and forming thereby an annular pressure space separate from the pressure space Within said cylinder.

ARTHUR A. BYERLEIN. 

